1. Field of the Invention
This invention relates to a pattern control device for flat knitting machines, which is made so that the controlling of the movements of yarn guides can be done accurately.
2. Description of the Prior Art
As shown in FIGS. 8-11, a conventional flat knitting machine consists of a pair of needle beds 51 arranged so as to have an inverse V section, a pair of carriages 52 which contain cams (not shown) for moving up and down the needles on the needle beds, and which are adapted to be moved back and forth in the lateral direction, a plurality of yarn guides 53 adapted to be moved with the carriage and feed yarn to the needles, and a ledge 54 on which wound knitting yarn is set up. The opposed carriages 52 are connected together by a saddle 66, and yarn guide operating pins 67 project downward from a horizontal portion of the saddle.
As shown in FIGS. 10 and 11, each of the yarn guides 53 constituting a principal portion of a pattern mechanism and provided with yarn feeders 65 at the lower ends thereof is fixed to a horizontal guide rail 55, which extends along a needle bed 51, via a yarn guide box 56 provided at the upper portion of the yarn guide 53, in such a manner that the yarn guide 53 can slide laterally (refer to the directions of arrows in FIG. 10), and the yarn guide box 56 is provided with a recess 60 in the upper surface thereof.
During a knitting operation, the yarn guide operating pin 67 extending downward from the saddle 66 engages the recess 60 suitably in accordance with a pattern, and the relative yarn guide is moved in accordance with a lateral movement of the carriage 52. The amount of movement of the yarn guide is determined depending upon the distance between opposed left and right yarn guide stoppers 61. Each of the yarn guide stoppers 61 is connected via a movable bar 59 to a female screw member 62 which can be displaced laterally by a horizontally extending elongated parent screw 58 engaged therewith and provided in a yarn guide operating member 57 (refer to FIG. 8) fixed on a frame so as to extend leftward. The amount of movement of this yarn guide stopper can be regulated laterally to a suitable extent along the horizontal guide rail 55 in the same manner as the yarn guide box 56.
When a yarn guide operating pin 67 on the carriage 52 collides with a cam portion 61a at the free end of a stopper 61, it is lifted along a cam surface thereof to disengage from the recess 60 in the yarn guide box 56, so that the yarn guide operating pin 67 is released from the yarn guide box 56, as is clearly understood from FIGS. 10 and 11. Accordingly, even when the carriage 52 is moved, the yarn guide box 56 is left stopped in contact with the yarn guide stopper 61. The parent screw 58 is adapted to be turned forward and backward suitably by a geared motor 64 connected directly thereto, in accordance with an instruction from an electronic controller (refer to FIG. 8) set on a side portion of a machine base.
In the above-described conventional pattern mechanism for a flat knitting machine, a yarn guide stopper 61 which collides with a yarn guide box 56 springs back in some cases due to the shock of collision. Consequently, an error occurs in a knitted pattern, so that the boundary lines between different color portions in the pattern become irregular. Moreover, it becomes necessary to provide a waiting time during an operation of transferring the yarn guide stoppers sequentially in accordance with the pattern, and a stop time occurs in the machine base. This causes the productive efficiency to lower. In addition, it is difficult to provide a large number of yarn guides in a narrow space.